Finding the Fourth Proportional to 1,456.78, 2,185.98 and 687.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,456.78 : 2,185.98 = 687.28 : x
2. Step 2: Convert to fraction form
   1,456.78/2,185.98 = 687.28/x
3. Step 3: Cross multiply
   1,456.78x = 2,185.98 × 687.28
4. Step 4: Simplify right side
   1,456.78x = 1,502,380.33
5. Step 5: Solve for x
   x = 1,502,380.33/1,456.78
6. Step 6: Final answer
   x = 1,031.30